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The gamma isoform of PI3Kinase (PI3Kγ) controls leukocyte chemotaxis by participating in GPCR signaling, and by regulating cellular polarization. Here we show that PI3Kγ is required for efficient induction of CXC chemokine receptor 3 (CXCR3) on T cells upon activation. T cells from PI3Kγ−/− mice up-regulated CXCR3 less efficiently than wild-type controls both upon activation in vitro as well as during Leishmania mexicana infection. Inhibition of PI3Kinases using wortmannin and LY294002 or blockade of PI3Kγ activity using a selective inhibitor or PI3Kγ siRNA suppressed induction of CXCR3 on T cells following activation. Levels of CXCR3 and T-bet mRNA were significantly lower in PI3Kγ inhibitor–treated T cells, indicating that PI3Kγ may control CXCR3 expression in part through induction of T-bet. These results reveal a novel role for PI3Kγ in the induction of CXCR3 on T cells and suggest that PI3Kγ may regulate leukocyte chemotaxis by controlling the expression of chemokine receptors.

The gamma isoform of PI3Kinase (PI3Kγ) controls leukocyte chemotaxis by participating in GPCR signaling, and by regulating cellular polarization. Here we show that PI3Kγ is required for efficient induction of CXC chemokine receptor 3 (CXCR3) on T cells upon activation. T cells from PI3Kγ−/−mice up-regulated CXCR3 less efficiently than wild-type controls both upon activation in vitro as well as during Leishmania mexicanainfection. Inhibition of PI3Kinases using wortmannin and LY294002 or blockade of PI3Kγ activity using a selective inhibitor or PI3Kγ siRNA suppressed induction of CXCR3 on T cells following activation. Levels of CXCR3 and T-bet mRNA were significantly lower in PI3Kγ inhibitor–treated T cells, indicating that PI3Kγ may control CXCR3 expression in part through induction of T-bet. These results reveal a novel role for PI3Kγ in the induction of CXCR3 on T cells and suggest that PI3Kγ may regulate leukocyte chemotaxis by controlling the expression of chemokine receptors.

Mice lacking both the p110γ and p110δ isoforms display severe impairment of thymocyte development. Here, we show that this phenotype is recapitulated in p110γ−/−/p110δD910A/D910A (p110γKOδD910A) mice where the p110δ isoform has been inactivated by a point mutation. Moreover, we have examined the pathological consequences of the p110γδ deficiency, which include profound T-cell lymphopenia, T-cell and eosinophil infiltration of mucosal organs, elevated IgE levels, and a skewing toward Th2 immune responses. Using small-molecule selective inhibitors, we demonstrated that in mature T cells, p110δ, but not p110γ, controls Th1 and Th2 cytokine secretion. Thus, the pathology in the p110γδ-deficient mice is likely to be secondary to a developmental block in the thymus that leads to lymphopenia-associated inflammatory responses.

Mice lacking both the p110γ and p110δ isoforms display severe impairment of thymocyte development. Here, we show that this phenotype is recapitulated in p110γ−/−/p110δD910A/D910A(p110γKOδD910A) mice where the p110δ isoform has been inactivated by a point mutation. Moreover, we have examined the pathological consequences of the p110γδ deficiency, which include profound T-cell lymphopenia, T-cell and eosinophil infiltration of mucosal organs, elevated IgE levels, and a skewing toward Th2 immune responses. Using small-molecule selective inhibitors, we demonstrated that in mature T cells, p110δ, but not p110γ, controls Th1 and Th2 cytokine secretion. Thus, the pathology in the p110γδ-deficient mice is likely to be secondary to a developmental block in the thymus that leads to lymphopenia-associated inflammatory responses.

Leukocyte trafficking to inflammatory sites is a gradual process, which is dominated in its early phases by chemokine- and cytokine-mediated neutrophil recruitment. The chemokine regulated on activation normal T cell expressed and secreted (RANTES) has been shown to be highly expressed in the joints of patient with rheumatoid arthritis and to promote leukocyte trafficking into the synovial tissue. In this study, we investigated the effect of RANTES in a murine model of peritoneal chemotaxis, and we found that RANTES dose-dependently induces neutrophil recruitment. Then, through morphological and histological analyses, we observed that activated neutrophils represent the major infiltrating population in response to RANTES chemotactic stimulus. Furthermore, we demonstrated that oral administration of either nonisoform-specific phosphoinositide 3-kinase (PI3K) inhibitor LY294002 (morpholin-4-yl-8-phenylchromen-4-one) or selective PI3Kgamma inhibitor AS041164 (5-benzo[1,3]dioxol-5-ylmethylene-thiazolidine-2,4-dione) blocks RANTES-induced chemotaxis and reduces the level of AKT phosphorylation. Because the two compounds showed a similar pharmacokinetic profile in terms of bioavailability and half-life after oral route administration, the selective inhibition of the PI3Kgamma-isoform pathway through AS041164 was three times more potent in reducing neutrophil recruitment. Finally, to confirm the blockade of neutrophil infiltration that occurs in the early phase of the inflammatory response, AS041164 was also tested in a model of carrageenan-induced paw edema in rats. Therefore, the PI3Kgamma pathway plays an important role in controlling neutrophil chemotaxis during early steps of inflammation.

Class I phosphoinositide 3-kinases (PI3Ks), in particular PI3Kγ, have become attractive drug targets for inflammatory and autoimmune diseases. Here, we disclose a novel series of furan-2-ylmethylene thiazolidinediones as selective, ATP-competitive PI3Kγ inhibitors. Structure-based design and X-ray crystallography of complexes formed by inhibitors bound to PI3Kγ identified key pharmacophore features for potency and selectivity. An acidic NH group on the thiazolidinedione moiety and a hydroxy group on the furan-2-yl-phenyl part of the molecule play crucial roles in binding to PI3K and contribute to class IB PI3K selectivity. Compound 26 (AS-252424), a potent and selective small-molecule PI3Kγ inhibitor emerging from these efforts, was further profiled in three different cellular PI3K assays and shown to be selective for class IB PI3K-mediated cellular effects. Oral administration of 26 in a mouse model of acute peritonitis led to a significant reduction of leukocyte recruitment.

Mono‐N‐ethylated α‐amino acid esters are obtained in high yields using reductive amination procedures. Formation of imine is achieved by excess of acetaldehyde, followed by removal of acetaldehyde and reduction by NaBH(OAc)3. The elaborated one‐pot synthesis allows for the efficient synthesis of side‐chain protected amino acid derivatives. Copyright © 1999 European Peptide Society and John Wiley & Sons, Ltd.

Mono-N-ethylated α-amino acid esters are obtained in high yields using reductive amination procedures. Formation of imine is achieved by excess of acetaldehyde, followed by removal of acetaldehyde and reduction by NaBH(OAc)3. The elaborated one-pot synthesis allows for the efficient synthesis of side-chain protected amino acid derivatives. Copyright © 1999 European Peptide Society and John Wiley & Sons, Ltd.

Artefenomel and DSM265 are two new compounds that have been shown to be well tolerated and effective when administered as monotherapy malaria treatment. This study aimed to determine the safety, pharmacokinetics, and pharmacodynamics of artefenomel and DSM265 administered in combination to healthy subjects in a volunteer infection study using the Plasmodium falciparum-induced blood-stage malaria model.

DSM265 is a novel antimalarial drug in clinical development that acts as a selective inhibitor of Plasmodiumdihydroorotate dehydrogenase. In a previous phase 1b study, a single 150-mg dose of DSM265 showed partial efficacy against experimentally induced blood-stage Plasmodium falciparummalaria (IBSM).

The phosphoinositide 3-kinase p110β subunit has noncatalytic functions; its catalytic activity is pertinent to both diabetes and cancer.